1. Field of the Invention
The present invention is directed to card clothing for a textile machine comprising a plurality of adjacent spaced-apart needles or serrated punched cut-outs disposed in rows, wherein the needles or serrated punched cut-outs are stamped and accordingly have a non-rectangular cross-sectional geometry, wherein a free passage zone for the fibers being combed is formed between the spaced-apart needles or serrated punched cut-outs.
2. Summary of the Invention
Card clothing of this type is used for various types of textile machines, e.g., circular combs, fixed combs, carding, etc. In this context it is already known to at least partially shape the needles or the tips of serrated punched cut-outs by means of stamping, i.e., cold forming, in order to thus alter the original round or rectangular cross-sectional configuration.
In the case of needles, for example, it is already known to impart to them a rhombic cross-sectional configuration so that, viewed in the direction of the relative movement between the sliver and the needles, the free passage between adjacent needles initially narrows in order to then widen again starting from the narrowest point.
This design, however, has the shortcoming that impurities may collect and become wedged in the narrowing zone in such a way that they can no longer be removed even with cleaning actions, e.g., a cleaning with compressed air.
With this as the starting point, the invention has as its object to improve card clothing of the above type in such a way that the cleaning effect or combing effect, respectively, are improved.
This object is met according to the invention in such a way that the free passage zone steadily widens viewed in the direction of travel of the sliver. This means, in other words, that the narrowest point of the passage zone is located, viewed more or less in the direction of the relative movement, at the outermost start of the passage so that a jamming and collecting of particles is prevented since particles that are to be combed out are either small enough so that they can pass through the passage or, if they have an even slightly larger diameter, they can fall off without jamming, or they are removed, at the latest, during the cleaning process.
In a further improvement of the invention, provision is made for the free passage zone to have a trapezoidal basic shape and for the needles or tips of the serrated punched cut-outs to be stamped such that they have a triangular or trapezoidal basic shape in cross section.
The triangle corners or trapezoid corners are advantageously rounded.
With the inventive design it is made possible that impurities such as boll fragments and grains of sand, which can collect in conventional card clothing, are only briefly retained due to the widening cross section in such a way that they make only point contact or linear contact at the beginning of the passage.
The result that is achieved in this manner is that the card clothing remains clean and consistent operating results are attained and the fibers can more easily be pulled through the barrier, i.e., an overall improved combing result. The long fiber content in the combing waste decreases and the machine can be optimally adjusted so that an improvement of the economic aspect is achieved. This also includes a longer life due to lesser wear on the card clothing. Lastly, boll fragments, burls and noils that are not pulled out are held back and a jamming of the boll fragments is prevented so that an altogether better combing result is attained.
Provision may furthermore advantageously be made for the needles or tips to be formed in cross section such that they have side surfaces that are convexly curved outward, a rounded front face viewed in the direction of the movement relative to the sliver, and a rear end face that tapers to a relatively sharp point.
In other words, the needles may, in cross section, have the profile of a symmetrical or asymmetrical aircraft wing.
This results in a flow along the needles similar to that of the aircraft wing, so that the fibers of the sliver are subjected to pressure fluctuations whereby impurities are loosened that would otherwise collect. Burls, dust and light-weight pieces are held back by the negative pressure.
The invention will be explained in more detail below, based on a preferred embodiment in conjunction with the drawing.